Selecting from hours of documentary footage and mixing fight sequences with interviews and photographs, director James Toback tells the story of the boxer's climb from his impoverished childhood to the pinnacle of his sport and dramatic fall.

Like Serbian director Emir Kusturica's documentary on soccer legend Diego Maradona, which is showing out of competition next week, "Tyson" paints the picture of a charismatic but troubled champion whose image transcended his own sport.

"In the course of the film, Tyson moves from someone you might think you'd want to steer well clear of to a man you might actually want to meet and speak with, which is a significant accomplishment," trade paper Variety said in its review.

Tyson himself, his face tattooed and looking significantly heavier in a grey suit than in the days of his prime, mounted the red carpet at the film's opening night to loud applause from onlookers and festival-goers.

The film treats the boxer, who became the youngest heavyweight champion of the world but was also banned for biting an opponent, as a tragic but also noble figure.

Toback, who has known Tyson for years, has been praised for the confidences he drew from a fighter whose brutality in the ring hid a more sensitive side.

His career was certainly dramatic enough. "Iron Mike" Tyson was the most recognizable figure in boxing during the 1980s and 90s, knocking out a string of opponents and earning and squandering hundreds of millions of dollars in the process.

Humiliated as a child for his distinctive high lisp, he suffered much bullying until he began to fight back.

He was rescued from the mean streets of Brooklyn by veteran trainer Cus D'Amato, who helped channel his raw power and aggression and made him one of the most devastating punchers the sport had ever seen.

At his peak, Tyson exerted total domination over opponents, apparently scaring several into submission before their fights had even started.

He fascinated the public but was increasingly stigmatized as violent and uncontrollable especially after his conviction and prison sentence for rape.

His fall from grace was cemented when he was banned for biting the ear of Evander Holyfield during a fight but despite the dark side, Toback paints the picture of a complicated man who is both searching and troubled.